Elon Musk sold a further US$1.02 billion of Tesla Inc. shares, taking him close to his target of reducing his stake in the electric-car maker by 10 per cent. 

The Tesla chief executive officer -- also the world’s richest person -- sold 934,090 shares, according to a filing with the U.S. Securities & Exchange Commission. 

Musk has been offloading Tesla stock since asking his Twitter followers in November whether he should sell some of his stake. Musk said in a tweet last week that he was “almost done” trimming his Tesla holding by 10 per cent.

The latest sale takes Musk’s total to about 15.6 million shares, for approximately US$16.4 billion. He’d need to dispose of about 17 million shares to offload 10 per cent of his stake, assuming his pledge excludes exercisable options. 

Tesla climbed 2.3 per cent in U.S. premarket trading. The shares have gained 54 per cent this year.

It’s unclear whether the poll in November had any actual bearing on Musk’s plans. He said months earlier that he was likely to exercise a big block of stock options toward the end of the year, and he set up a trading plan to sell shares before his tweet.

Musk has a net worth of US$278.9 billion, up almost 80 per cent this year, according to the Bloomberg Billionaires Index.